What Could be Done Further?

These are just random "brainstorming" type ideas I've had that might improve things further at considerably less cost.  After dropping a huge chunk of change on what we just did, I'm not inclined to rush out and spend more money.  I'll probably spend at least one winter just with this, just to see what the net effects are.  But if anyone has any suggestions, please contact me at:

1. Increase the R-value in the attic.  We had previously brought the attic up to R-50.  For another $1000, we could probably increase this to R-100.  No idea whether this would do any good.  We originally added the attic insulation in the summer of 2006, and in the winter of 2006-7 did not notice any appreciable decrease in heating requirement, but that may have been because the rest of the house was so badly insulated.

2. Insulate the interior of the basement walls maybe up to R-10 or R-15.  I'm not sure what this would set us back (another $10,000?), but it might enable us to survive the winter in the basement with no heat at all.

3. Add storm windows.  Since we missed our opportunity to get R-9 windows, maybe this would help the main deficiency in insulation right now.  Of course with unlimited money, we'd just replace the windows with the new R-9 type windows, but I'm thinking that storm windows might do just as good a job.